Also, police and hospital officials say local al-Qaida militants attacked a police station near Fallujah, west of Baghdad, killing two police officers. They say the gunmen used explosives to destroy the station after other officers fled.

All officials spoke on condition of anonymity because they were not authorized to talk to journalists.

Violence has escalated in Iraq over the past year, particularly since late last month after authorities dismantled a Sunni anti-government protest camp and arrested a Sunni lawmaker.